terminology.pdf

1THE INTERNATIONAL BUREAUFOR THE STANDARDISATION

OF MAN-MADE FIBRES

Terminologyof man-made fibres

2000 Edition(replaces the 1994 edition)

BISFA

TerminologyBISFA 2000

2

BISFA wishes to acknowledge and thank the members of the Standards for Fibresand Textiles Committee for their contribution to the production of his booklet, andespecially the following individuals :

Mr. P. LATZKE, of Acordis, Germany (Chairman of the Terminology Working Group)Dr. A. KRIEGER, Secretary General of BISFAMr. B. ERGUN, of DuPontSA, TurkeyMr. A. GOMES DA SILVA, of Fisipe, PortugalDr. O. JOHN, of DuPont de Nemours International, SwitzerlandMr. Ph. LAPERSONNE, of Rhodia Performance Fibres, FranceMrs. U. PLIETE, of Bayer Faser, GermanyDr. F. PREZZAVENTO, of Assofibre, ItalyMr. Ch. RAMSAUER, of Lenzing, AustriaMrs. J. KRHOV, of Spolana, Czech RepublicMr. B. TABOR, of Acordis, the NetherlandsMrs. A. WHINERAY, of Acordis, UK

Copyright BISFA 2000All rights reserved. Unless otherwise specified, no part of this publicationmay be reproduced or utilised in any form or by any means, electronic ormechanical, including photocopying and microfilm, without permissionfrom the publisher.

BISFAAvenue E. Van Nieuwenhuyse, 4B - 1160 BrusselsBelgium


3

Page

PREFACE................................................................................................................................. 4

CHAPTER 1 Generic names of man-made fibres .......................................................... 5

1.1 Generic fibre names ............................................................................... 51.2 Generic classification of cellulosic fibres .............................................. 81.3 Generic classification of synthetic fibres.............................................101.4 Generic classification of inorganic fibres ............................................131.5 Coding system of man-made fibres ....................................................14

CHAPTER 2 Morphological schemes .............................................................................15

2.1 BISFA definition of "fibre"-related terms.............................................162.2 Characteristics of man-made fibre cross sections.............................172.3 General morphological scheme of man-made fibres ........................192.4 Illustration of yarn constructions ..........................................................202.5 Morphological scheme for elastane containing yarns .......................21

CHAPTER 3 Technical terms and definitions ...............................................................23

CHAPTER 4 Statistical terms and definitions ...............................................................48

4.1 Definitions...............................................................................................484.2 Basic statistics .......................................................................................494.3 Statistical Process Control Parameters (SPC) ..................................56

CHAPTER 5 Designation of yarns in the tex system...................................................58

5.1 Textile yarns ...........................................................................................585.2 Steel tyre cord........................................................................................605.3 Open cord constructions.......................................................................62

CHAPTER 6 Application of SI units to man-made fibres............................................63

6.1 Base units of the International System (SI) ........................................636.2 Derived units ..........................................................................................646.3 Multiples and sub-multiples..................................................................656.4 Principal SI units in use for textiles......................................................66

CHAPTER 7 Translation of technical terms ..................................................................69

CONTENTS


4

In 1968, recognising a need to avoid a confusion of technical terms, BISFA publishedits first Terminology booklet. This contained those terms and definitions whichdescribe the different forms in which man-made fibres are available, either as primarymaterial or intermediate products. With the objective of avoiding translation difficultiesand consequent misunderstanding, the booklet also contained a list in five languagesof the principal technical terms used in the various internationally agreed methodsbooklets.

This booklet was revised in 1977, when new sections were added containingdefinitions of technical terms used in BISFA methods booklets, an explanation of theSI system of units, and a description of the ISO system for designating yarns in thetex system.

The revision of 1994 introduced the generic names. This edition having sold out wasreprinted in 1997. Two elements have been added: definitions for airborne fibrousmaterials and an overview of ISO definitions to describe the accuracy of a measuringmethod and the currently used definitions for statistical process control.

In 1999, a complete review of the whole booklet was undertaken, adding oreliminating numerous details. The layout was changed. Terms in differentlanguages are presented in a comprehensive view.

The definitions have been written with due consideration of recognised referencebooks such as Textile Terms and Definitions (The Textile Institute, 10th edition 1995),Dictionary of Man-made Fibres (H. Koslowski, International business press, 1st

edition 1998), Handbuch der Faser (G. Schnegelsberg, Deutscher Fachverlag 1999),Textile Dictionary (several languages, by ITS). Relevant ISO, CEN and ASTMstandards were taken into account where appropriate.

The terms and definitions are given in English in alphabetical order. A separatechapter contains the translations of terms into French, German, Italian, Spanish, and,for the first time Czech, Portuguese and Turkish languages. In the case of a disparitybetween languages the English text is to be used.

PREFACE


5

1.1 Generic fibre names

General introduction

The chapter 1 provides a classification of the various categories of man-made fibres.Each of these categories is designated by a generic name and its definition. Genericnames are generally used :

for customs purposes

in defining public sector transactions

in technical standards

in textile product labelling.

Through the EU Directive and related national legislation the fibre content of textilearticles must be stated at point of sale using the generic names.

BISFA is careful to restrict this classification to those categories of man-made fibreswhich are produced on an industrial scale or are of commercial significance forspecial purposes and traded internationally. Fibres which have recently emergedfrom research or which are still at the stage of development are not included. Ageneric fibre name can cover different chemical substances. The table of genericnames includes non exhaustive examples of chemical formulae representative of thedifferent fibre categories. The producers in BISFA have also adopted a codingsystem based on generic names as an aid to communication.

BISFA defines generic fibre names only (which are then found in ISO standard 2076and in EU regulations). BISFA does not define specific substances (polymers,copolymers, etc).

Generic names are completely distinct from trademarks which are used by individualproducers to identify their own products

CHAPTER 1Generic names of man-made fibres


6

Naming mixtures

For naming of fibres containing mixtures of chemically distinct, and not chemicallylinked polymers or copolymers, the following rules should be applied :

a) Whereas copolymers may, if necessary, be assigned distinctive generic names,the creation of new generic names for fibres composed of chemically distinctpolymers shall be discouraged.

b) When the proportion of one of the polymers or copolymers reaches 85 % bymass, the fibre takes the generic name corresponding to this component.

c) When none of the components reaches 85 % by mass, then either a new genericname must be used or the fibre must be identified as a simple mixture e.g. x %poly A, y % poly B. Each such case shall be examined on its merits.


7

Generic fibre names with their codes

Fib

res

Nat

ura

lM

an-m

ade

Org

an

ic

In

org

an

ic

By

tra

ns

form

ati

on

of

Fro

m s

yn

theti

c p

oly

me

rs :

natu

ral

po

lym

ers

:

Ace

tate

CA

Acr

ylic

PA

N C

arbo

nC

FA

lgin

ate

AL

GA

ram

idA

R C

eram

icC

EF

Cup

roC

UP

Chl

orof

ibre

CL

F G

lass

GF

Ela

stod

iene

1 (r

ubbe

r)E

DE

last

ane

EL

Me

tal

MT

FLy

ocel

lC

LY

Ela

stod

iene

E

DM

odal

CM

DF

luor

ofib

reP

TF

ET

riace

tate

CT

AM

elam

ine

MF

Vis

cose

CV

M

odac

rylic

MA

CP

olya

mid

eP

AP

olye

ste

r2

PE

SP

olye

thyl

ene

1 P

EP

olyi

mid

eP

I1

Pol

yeth

ylen

e an

d p

olyp

ropy

lene

are

pol

yole

fins

Pol

ypro

pyle

ne1

PP

2 T

he s

ame

code

is u

sed

in t

he p

last

ic in

dust

ryV

inyl

alP

VA

L

for

po

lye

the

r su

lfone

(IS

O 1

043)


8

1.2 Generic classification of cellulosic fibres

Generic name Distinguishing attribute Examples of chemical formulae

acetate Cellulose acetate fibre in whichless than 92 %, but at least 74%, of the hydroxyl groups areacetylated.

Secondary cellulose acetate:

C6H7O2 (OX)3n

Where X = H or CH3CO and the degree of esterificationis at least 2,22 but less than 2,76

triacetate Cellulose acetate fibre in whichat least 92 % of the hydroxylgroups are acetylated.

Cellulose triacetate

C6H7O2 (OX)3n

Where X = H or CH3CO and the degree of esterificationis between 2,76 and 3

alginate Fibre obtained from the metalsalts of alginic acid

Calcium alginate:

cupro Cellulose fibre obtained by thecuprammonium process

Cellulose:

OCH2OH

O

OH H

H

H

H

O

n

OH

CH2OH

H

H

OH

OH

H

OH

H H

OCOO-

O

OH H

H

H

H

O

n

OH

COO-

H

H

OH

H

OH

H

OH

H

Ca2+


9

1.2 Generic classification of cellulosic fibres


lyocell Cellulosic fibre obtained by anorganic solvent spinningprocess. It is understood that:1) an organic solvent meansessentially a mixture of organicchemicals and water, and2) solvent spinning meansdissolving and spinning withoutthe formation of a derivative.

Cellulose:

modal Cellulose fibre having a highbreaking force1 BF and a highwet modulus Bw.

The breaking force BFc in theconditioned state and the wetmodulus Fw required toproduce an elongation of 5 %In its wet state are :

LDF

LDLDBF

w

c

5,0

23.1

+

where LD is the mean lineardensity (mass per unit length)in decitex.BFc and Fw are expressed incentinewtons.

Cellulose:

viscose Cellulose fibre obtained by theviscose process

Cellulose:

1 ISO 2076 uses the term "strength"

OCH2OH

O

OH H

H

H

H

O

n

OH

CH2OH

H

H

OH

OH

H

OH

H H

OCH2OH

O

OH H

H

H

H

O

n

OH

CH2OH

H

H

OH

OH

H

OH

H H

OCH2OH

O

OH H

H

H

H

O

n

OH

CH2OH

H

H

OH

OH

H

OH

H H


10

1.3 Generic classification of synthetic fibres


acrylic Fibre composed of linearmacromolecules having in thechain at least 85% by mass ofacrylonitrile repeating units.

Polyacrylonitrile:

and acrylic copolymers

aramid Fibre composed of linearmacromolecules made up ofaromatic groups joined byamide or imide linkages, atleast 85% of the amide orimide linkages being joineddirectly to two aromatic ringsand the number of imidelinkage, if the latter arepresent, not exceeding thenumber of aramide linkages.

Example 1:

Example 2:

Note: in example 1 the aromatic groups may be the same or different

chlorofibre Fibre composed of linearmacromolecules having in thechain more than 50% by massof vinyl chloride or vinylidenechloride units (more then 65%in the case in which the rest ofthe chains is made up ofacrylonitrile, the modacrylicfibres being thus excluded.)

Poly(vinyl chloride):

AndPoly(vinylidene chloride):

elastane Fibre composed of at least85% by mass of a segmentedpolyurethane and which, ifstretched to three times itsunstretched length, rapidlyreverts substantially to theunstretched length when thetension is removed.

Macromolecules having alternate elastic and rigidsegments with repetition of the group

CH2

C

CNn

H

C

O O

C N Nn

H H

C

C

C

N

O

O

O

n

N

H

CH2

C

Cln

H

C

Cl

CH2

Cln

O C N

O H

CH2 C

CNp

CH3 C

X

Ym

n

H


11



elastodiene Fibre composed of natural orsynthetic polyisoprene, or ofone or more dienespolymerized with or withoutone or more vinyl monomers,and which, if stretched to threetimes its unstretched length,rapidly reverts substantially tothe unstretched length whenthe tension is removed.

Natural polyisoprene extracted from latexHeves brasilienisis, vulcanized

fluorofibre Fibre composed of linear ma-cromolecules made from ali-phatic fluorocarbon monomers.

Polytetrafluorethylene

C

F

C

F

FFn

melamine Fibre composed of at least 50% by mass of cross-linkedmacromolecules made up ofmelamine methylol poly-condensate.

Melamine

N

NN

N

N

N **HH

H

n

modacrylic Fibre composed of linearmacromolecules having in thechain at least 50% and lessthan 85% by mass ofacrylonitrile.

Acrylic copolymers

If X = H and Y = Cl:Poly(acrylonitrile or vinyl chloride)

If X = Y = Cl:Poly(acrylonitrile or vinylidene chloride)

polyamideornylon

Fibre composed of linearmacromolecules having in thechain recurring amide linkages,at least 85% of which arejoined to aliphatic cycloaliphaticunits.

Polyhexamethylene adipamide (polyamide 66)

Polycaproamide (polyamide 6)

C CC H2 C H2

Sx

C H3

C CC H2 CH 2

C H3

H

H

CH2 C

CNp

CH3 C

X

Ym

n

H

CN CH2

N C6

CH2

O O

n

4

H H

N CH2

C5

O n

H


12



polyester Fibre composed of linearmacromolecules having in thechain at least 85% by mass ofan ester of a diol andterephthalic acid.

Poly(ethylene terephthalate)

polyethylene1 Fibre composed of linearmacromolecules ofunsubstituted saturatedaliphatic hydrocarbons.

Polyethylene

polyimide Fibre of synthetic linearmacromolecules having in thechain recurring imide units.

Polyimide

polypropylene1 Fibre composed of linearmacromolecules made up ofsaturated aliphatichydrocarbon units in which onecarbon atom in two carries amethyl side group, generally inan isotactic configuration andwithout further substitution.

Polypropylene

vinylal Linear macromolecules of poly(vinyl alcohol) with differentlevels of acetalization

Acetalized poly(vinyl alcohol)

CH2 CCCH2OH

CH2

O

C

OR

m

n

p

H H H

Where n > 0

1 Forms part of the polyolefins class

C O CH2

O O

CH2 O n

C

CH2 CH2 n

CC

CN*

O

OC

C

N R1 .2 "

O

OO

*

n

R1 = ArylR2 = Alkyl

CH2

Cn

CH3

H


13

1.4 Generic classification of inorganic fibres

Generic name Distinguishing attribute

carbonFibre containing at least 90% by mass ofcarbon obtained by thermal carbonization oforganic fibre precursors

glass Fibre, in textile form, obtained by drawingmolten glass.

ceramic Fibre, in textile form, obtainedfrom ceramic materials

metal1Fibre obtained from metal

1

Fibres can be coated with metals, in which case they are described as "metallized fibres" and not "metal fibres"


14

1.5 Coding system of man-made fibres

Alphabetic order of names Alphabetic order of codesacetate CA ALG alginate

acrylic PAN AR aramid

alginate ALG CA acetate

aramid AR CF carbon

carbon CF CEF ceramic

ceramic CEF CLF chlorofibre

chlorofibre CLF CLY lyocell

cupro CUP CMD modal

elastane EL CTA triacetate

elastodiene ED CUP cupro

fluorofibre PTFE CV viscose

glass GF ED elastodiene

lyocell CLY EL elastane

melamine MF GF glass

metal MTF MAC modacrylic

modacrylic MAC MF melamine

modal CMD MTF metal

polyamide PA PA polyamide

polyester PES1 PAN acrylic

polyethylene PE PE polyethylene

polyimide PI PES1 polyester

polypropylene PP PI polyimide

triacetate CTA PP polypropylene

viscose CV PTFE fluorofibre

vinylal PVAL PVAL vinylal

1 The same code is used in the plastic industry for polyether sulfone in ISO 1043.


15

INTRODUCTION

This chapter gives an overview on terms directly related to "fibres" and sets out indiagrammatic form the relationship between the various forms into which fibres canbe transformed, up to and including the twisting stages. The diagrams cover only themain sequences of commonly used operations, and should not be interpreted asimplying that all morphological forms listed exist for a particular generic category.Definitions are given for the main cases of elastane containing yarns.

Each term in these diagrams is defined in Chapter 3.

2.1 BISFA definitions of "fibre" related terms

CHAPTER 2Morphological schemes

BIS

FA

def

init

ion

s o

f "f

ibre

" re

late

d t

erm

s

Fib

re:

a m

orph

olog

ical

term

for

subs

tanc

es c

hara

cter

ised

by

thei

r fle

xibi

lity,

fine

ness

an

d h

igh

ra

tio o

f le

ng

th to

cro

ss s

ect

ion

al a

rea

Fila

men

t: a

fibr

e of

ver

y gr

eat l

engt

h, c

onsi

dere

d as

con

tinuo

usY

arn:

a te

xtile

pro

duct

of s

ubst

antia

l len

gth

and

rel

ativ

ely

smal

l cro

ss s

ectio

n,co

mpo

sed

of fi

bres

with

or

with

out t

wis

t. T

his

gene

ral t

erm

cov

ers

all t

he s

peci

ficty

pes

of y

arns

, e.g

. sin

gle

yarn

, mul

tiple

wou

nd y

arn,

fila

men

t yar

n, s

pun

yarn

Ma

n-m

ad

e f

ibre

sp

inn

ing

pro

ce

ss

le

ad

s t

o:

To

w:

a la

rge

num

ber o

f fila

men

ts, a

ssem

bled

with

out

subs

tant

ial t

wis

t usu

ally

inte

nded

to b

e cu

t or

stre

tch-

brok

en fo

r us

e in

sta

ple

fibre

or

top

form

Fib

ril:

a s

ubdi

visi

on o

f a fi

bre

can

be

att

ach

ed

to th

e fi

bre

or

loo

se

incr

easi

ng u

nit l

engt

h

in

crea

sing

uni

t len

gth

Fib

re f

ly: a

irbo

rne

fibre

so

r p

art

s o

f fib

res

(lig

ht

enou

gh to

fly)

, vis

ible

as

fibre

s to

the

hum

an e

ye

Flo

ck: v

ery

shor

t fib

res,

inte

ntio

nally

pro

duce

dfo

r oth

er p

urpo

ses

than

spin

ning

Sta

ple

fib

re: a

text

ile fi

bre

of li

mite

d bu

t spi

nnab

le le

ngth

.F

ilam

ent

a fib

re o

f ver

y gr

eat l

engt

h,co

nsi

de

red

as

cont

inuo

us

T

exti

le(T

extil

e sp

inni

ng p

roce

ss le

ads

to:)

Sliv

er:

an

inde

finite

ly lo

ng a

ssem

bly

of s

tapl

e fib

res,

subs

tant

ially

par

alle

l, w

ithou

t tw

ist,

cap

able

of b

eing

draf

ted

in p

repa

ratio

n fo

r sp

inn

ing

.To

p =

syn

onym

for

sliv

er

sp

inn

ing

Ro

vin

g: a

n in

defin

itely

long

ass

embl

y of

sta

ple

fibre

s,su

bsta

ntia

lly p

aral

lel,

with

slig

ht tw

ist,

cap

ab

le o

f be

ing

draf

ted

in th

e la

ter

or fi

nal s

tage

s of

pre

para

tion

for

spin

nin

g.

p

roc

es

sS

pu

n y

arn:

a y

arn

mad

e of

sta

ple

fibre

s us

ually

bon

ded

toge

ther

by

twis

t.F

ilam

ent

yarn

: a

ya

rn c

om

po

sed

of o

ne o

r mor

e fil

amen

ts

Mo

no

fil:

a fil

amen

t yar

n co

nsis

ting

of a

sin

gle

filam

ent

Sin

gle

yar

n: a

yar

n co

mpo

sed

of s

tapl

e fib

res

(spu

n ya

rn),

a s

ingl

e fil

amen

t (m

onof

ilam

ent)

or

seve

ral f

ilam

ents

(m

ultif

ilam

ent)

, w

ith o

r w

ithou

t tw

ist

16 TerminologyBISFA 2000


17

2.2 Characteristics of man-made fibre cross sections

circular profiled

angulare.g. triangular

lobale.g. trilobal

serrated ovale.g. bean-shaped

ribbonlike

Cross sectional shape


18

Cross sectional areaExamples:

solid hollow

Multi-component fibresExamples:

concentric cover-core sheath-corematrix / fibrill


19

2.3 General morphological scheme for man-made fibresS

tap

le f

ibre

To

wF

ilam

ent

yarn

Flo

ck

S

liver

or

top

Mo

no

fila

men

tM

ult

ifila

men

t

y

arn

yarn

Ro

vin

g

S

pu

n y

arn

Fla

t ya

rn

Tex

ture

d

Inte

rlac

ed

ya

rn

yarn

Sin

gle

yar

n

Fo

lded

yar

nC

able

d y

arn

or

cord

Mu

ltip

le w

ou

nd

yar

n


20

2.4 Illustration of yarn constructions

Definition Explanation

Spun yarn orFilament yarn

single Two or more componentsno twisting operation

Two or more componentsone twisting operationsimilar or dissimilar components

Two or more componentsmore than one twisting operationsimilar or dissimilar components

Single yarnSingle yarn

Multiple wound yarn

yarnyarn

Multiple wound yarn

yarnyarn

Folded (plied yarn)

singleyarnsingleyarn

Folded (plied yarn)

singleyarnsingleyarn

Cabled yarn

single yarn

folded yarn

single yarn

folded yarn

Cabled yarn

single yarn

folded yarn

single yarn

folded yarn

similar or dissimilar components


21

2.5 Morphological scheme for elastane containing yarns

Elastic covered yarn

General term for elastic yarn with bare elastane core covered by one or morerelatively inelastic textile components.

Several processes are in use to combine elastane with other fibres to produceelastic yarns for textile applications. The main yarn constructions of such fibrecombinations are :

Single or double covered yarnElastic yarn with bare and twistless elastane core and one or more relativelyinelastic yarns wrapped around the core with continuous turns in one oropposite directions.

Elastic core spun yarnsElastic yarn with bare elastane core and relatively inelastic staple fibres from asliver twisted around the core with continuous turns in one direction.


22

Elastic core twisted yarnsElastic yarn with bare elastane core and one or more relatively inelastic coveryarns twisted with continuous turns in one direction.

Elastic air covered yarnsElastic yarn with bare and twistless elastane core and one or more relativelyinelastic cover yarns air-mingled together with the core entwined by thefilaments with randomly distributed interlace points.

Core textured yarnElastic yarn with bare elastane core covered by one or more relatively inelasticcover yarns continuously textured together with the core entwined by thefilaments with false twist turns of randomly changing directions.


23

This chapter lists the technical terms used by BISFA in its various methods bookletstogether with their definitions. The terms are listed in alphabetical order.The translation of these terms into languages other than English is set out in Chapter 7.The definitions of the statistical terms used by BISFA are given in Chapter 4.Special definitions relevant to tests on steel tyre cord are to be found in the BISFA testmethods booklet for steel tyre cord.

Adhesion

The property denoting the ability of a material to resist delamination or separation intotwo or more layers.

Adhesion, in tyre fabricsThe force required to separate a textile material or steel cord from rubber or otherelastomer by a definite prescribed method.

Adhesion, rubber coverage

Ratio between the wire surface covered by rubber and total embedded surface after theadhesion pull out test.

Air-covered yarn

Elastic yarn with bare and twistless elastane (or other elastic) core covered by one ormore relatively inelastic cover yarns mingled together by an air stream with the coreentwined by the filaments with randomly distributed interlacing points.

Air textured yarn

Textured filament yarn obtained by overfeeding filament yarn into a turbulent stream ofair.

Assembled yarn

See : Multiple wound yarn

CHAPTER 3Technical terms and definitions


24

Atmosphere

Standard atmosphere :Air at local atmospheric pressure with a relative humidity of 65 % and a temperatureof 20 C.

Standard atmosphere for testing

The atmosphere in which the physical testing is carried out shall be the standardatmosphere maintained within the following limits :

Humidity : 2%Temperature : 2C

Note : For some materials which are known to be relatively unaffected by changes inrelative humidity, (e.g. polyester, acrylic) the tolerance of relative humidity canbe widened to 5%.

Atmosphere for preconditioning

The atmosphere used to partially dry the material before further treatment orconditioning. The atmosphere for preconditioning shall be maintained within thefollowing limits :

Humidity : 5 - 25 %Temperature : not exceeding 50 C

BCF (Bulked Continuous Filament)

Continuous filament fibre containing a degree of crimp or bulk.

Beam

A cylinder usually with flanges on each end on which a defined number of ends arewound substantially parallel with identical length.

Back beamA beam with a defined number of ends and defined length normally intended forsubsequent assembly with other back beams.

Warp knitting beam

A beam with a defined number of ends and length used for subsequent warp knittingoperation.

Weavers beam

A beam carrying the warp which has a defined number of ends of identical lengthinserted in the loom and used for weaving the fabric.


25

Bicomponent fibre

See : Multicomponent fibre.

Bishrinkage yarn

Yarn comprising filaments with two different shrinkage properties.

Boiling water shrinkage

See : Shrinkage.

Breaking elongation (deprecated term)

See : Elongation at break.

Breaking force (Synonym: Force at break)

The maximum force applied to a test specimen carried to rupture during a tensile test(See diagram).

Figure 3.1 : Force-Elongation-Diagram

Breaking strength (Synonym : Strength at break)

Term still commonly used, but improperly, for the average of the results of breaking forcemeasurements.

Breaking tenacity (Synonym : Tenacity at break)

The breaking force divided by the linear density of the unstrained material.

Force at Break

Force at Rupture

Elo

ng

atio

n

atB

reak

Elo

ng

atio

n

at

Ru

p-

ture

Elongation (%)

Fo

rce


26

Breaking toughness

The work required to achieve the breaking force of the test specimen expressed per unitlength and linear density of the unstrained material.

Bulked Continuous Filament

see BCF

Cabled yarn

A yarn with two or more components of which at least one is a folded yarn, combined byone or more twisting operations.Note : For certain industrial uses the word cord is used for folded or cabled yarns.

Chord modulus

See : Modulus

Clamps

The parts of a testing device which are used to grip the test specimen by means ofsuitable jaw faces.

Coating of steel filament

Mass of coatingThe quantity of covering layer applied to the surface of the filament.

Thickness of coating

The average thickness of the coating layer.

Composition of coating

The quantity of each of the components expressed as a percentage of the total massof the coating

Coiling

The process of laying down a sliver, top or tow into successive layers within whichcircular spirals are regularly arranged.

Commercial mass

See : Mass

Compact cord

A cord comprising a number of filaments twisted in the same direction and with thesame lay length with a minimum cross-sectional area.


27

Conditioned state

A sample is in the "conditioned state" or "conditioned" for testing purposes when it hasbeen kept in the atmosphere for testing until moisture equilibrium has been reached.Equilibrium shall be considered to have been attained when the mass of the well-opened sample shows no progressive change between successive hourly weighings. Inthe case of certain fibres, preconditioning is necessary to ensure that moistureequilibrium is reached by absorption.

Conditioning

The process of bringing a textile material into moisture equilibrium with the standardatmosphere for testing.

Consignment

All the products of one defined type and quality, delivered to one customer against onedispatch note.

Consignment sample

A selection of containers representative of the whole consignment.

Constant rate of extension (CRE) dynamometer

A tensile testing machine, where one clamp is stationery whilst the other is moving witha constant speed throughout the test, and where the entire testing system is virtually freefrom deflection.

Container

The unit of packaging (e.g. carton, case, bag, bale, etc.).

Conventional allowance

The conventional allowance is an agreed percentage to be added to the oven-dry massof the material for the calculation of commercial mass and certain other properties.This allowance is normally fixed for each fibre type and includes the moisture regainwhich approximately corresponds with equilibrium under the standard atmosphere andfor some fibres, an allowance for substances removable during normal processing, e.g.the finish normally applied to impart the required properties to the textile material.See Mass.

Cord

See : Cabled yarn, Steel cord.

Cord of steel

See : Steel Cord


28

Cord thickness

A conventional way of expressing an average cord diameter.

Core (in steel tyre cord)

A filament, filaments or strand that serves as an extended axis about which otherelements can be wound.

Core-spun yarn

Yarn with filament (elastane, other elastic or inelastic) core and relatively inelastic staplefibres from a sliver twisted around the core with continuous turns in one direction.

Core-textured yarn

Yarn with filament (elastane, other elastic or inelastic) core covered by one or morerelatively inelastic cover yarns continuously textured together with the core entwined bythe filaments with false twist turns of randomly changing directions.

Core-twisted yarn

Yarn with filament (elastane, other elastic or inelastic) core and one or more relativelyinelastic cover yarns twisted with continuous turns in one direction.

Covered yarn (single or double)

Yarn with filament (elastane, other elastic or inelastic) core covered by one or morerelatively inelastic cover yarns continuously wrapped around the core in one or oppositedirections.

Crimp

The waviness of a fibre, yarn or tow.Note : This characteristic may be expressed numerically by the combination of the

crimp frequency either with the crimp contraction or -in the case of textured yarns-with the crimp elongation.

Crimp contraction (also : percentage crimp)

The contraction of a crimped fibre or a textured yarn owing to the development ofcrimp, expressed as a percentage of its straightened length.

Crimp elongation

The lengthening of a crimped fibre or of a textured yarn after development of crimpwhen it is straightened under specified tension expressed as a percentage of itsinitial length.


29

Crimp frequency

The number of crimps per unit of length of filament yarn, staple fibre or tow.Note : Different methods are in common use for expressing crimp frequency, based

on half or whole waves and on straightened or unstraightened length.These bases must therefore be specified in any quantification.

Crimp, latent

Crimp that can be developed by a thermal treatment or by tensioning and subsequentrelaxation.

Crimp liveliness

The tendency for a textured yarn to develop its crimp immediately after the reductionof an applied tension.

Crimp stability

The ratio of the crimp of a fibre or textured yarn after a specified treatment to thecrimp prior to treatment, expressed as a percentage.Note : The method for determination of crimp and the treatment must be reported.

Cross section

The shape of a fibre when viewed perpendicular to its axis.Note : The shape of man-made fibres can be influenced by the spinning process and

subsequent processing and treatments, such as texturizing.

Delustrant

A chemical substance added to the polymer in order to reduce the lustre or transparencyof a fibre.

Dip

A chemical composition applied to a cord or fabric to improve its adhesion to rubber orelastomers.

Direction of lay

See : Twist

Durability (Stability)

The ability of a material to retain its physical or chemical properties after exposure for aspecified time under defined conditions such as heat, chemical agents, light or otherenvironmental processes.


30

Dust ; fibre dust

Non-specific terms. Can cover many types of fibrous and non fibrous species, includingcontaminants, usually present as mixtures of particulate matter. Recommended specificterms for airborne fibrous material are fibre fly, particulates from fibres, respirable fibre-shaped particulates (RFP).

Fibre fly

Airborne fibres or parts of fibres (light enough to fly), visible as fibres to the humaneye.

Particulates from fibresAirborne particles, not visible as fibres to the naked eye. May or may not be of thepolymer material of the fibre or have fibre shape under microscopic view.

Fibril

A subdivision of a fibre. A fibril can be attached to the fibre (fibrillated fibres) or canbe loose, independent.

Respirable fibre-shaped particulates (RFP)

Airborne particulates fulfilling the following dimensional conditions: length > 5 m anddiameter < 3 m and length/diameter ratio of > 3:1.

Edge crimped yarn

A textured filament yarn obtained by drawing heated filament yarn over an edge of smallradius of curvature.

Elasticity

That property of a material by virtue of which it tends to recover its original size andshape immediately after removal of a deforming force.

Elongation

The ratio of the extension of a test specimen to its initial length, expressed as apercentage.

Elongation at break

The elongation of a test specimen produced by the breaking force (See Fig. 3.1).

Elongation at rupture

The elongation of a test specimen corresponding to rupture (See Fig. 3.1).

Elongation at specified force

The elongation of a test specimen produced by a specified force.


31

Elongation at specified tenacity

The elongation of a test specimen produced by a specified tenacity.

Elongation between defined forces

The increase in length of a test specimen which results from subjecting it to twospecified forces.

End

An individual yarn used in or part of a specific textile assembly such as yarn sheets,warps, yarns on beam.

Extension

The increase in length of a test specimen produced by a force, expressed in units oflength.

False twist stretch yarn

A false twist yarn which has a high crimp elongation or high crimp contraction.

False twist yarn

A torsion textured yarn obtained by a continuous process applying high twist, heatsetting and untwisting.

Fibre

A morphological term for substances characterised by their flexibility, fineness and highratio of length to cross sectional area.

Fibre dust

See: Dust, fibre dust

Fibre length

Mean length:

The arithmetic mean of the lengths of staple fibres.Note : In the case of square cut staple fibres this mean is limited to the "central"

section of the frequency distribution.See Chapter 4: Statistics

Nominal length:

The length quoted on commercial documents.

Fibril

See: Dust, Fibre dust


32

Filament

A fibre of very great length, considered as continuous.See also: Steel Filament.

Filament yarn

A yarn composed of one or more filaments.Note : Filament yarns can have the following morphologies: flat, interlaced, twisted,

twistless, textured or combinations of these.

Finish

A chemical composition applied to yarns in order to facilitate processing.

Flame resistance

The property of a material whereby flaming combustion is slowed, terminated orprevented.Note : Flame resistance can be an inherent property of the basic material or it may be

imparted by specific treatment. The degree of flame resistance exhibited by amaterial during testing may vary with the test conditions.

Flare

The spreading of the filament ends or the strand ends at the cut end of a cord.

Flock

Very short fibres, intentionally produced for other purposes than spinning (e.g.: flocking).

Fly

See : Dust

Folded yarn (Synonym: Plied yarn)

A yarn in which two or more single yarns are combined by a single twisting operation.

Folding in layers

The process of placing a sliver, top or tow into successive layers in which each layer ismade of regular parallel folds.

Force

See : SI units Chapter

Force at break

See: Breaking force


33

Force at rupture

The final force just before complete rupture of a test specimen (See Fig. 3.1 : Force-Elongation diagram).

Force at specified elongation

The force associated with a specified elongation on the force-elongation curve.

Gauge length

The distance between two effective clamping points of a testing device.

Gear crimped yarn

Textured filament yarn obtained by passing the yarn between a pair of intermeshedtoothed wheels.

Giant carton

A container comprising a large number of packages arranged in several layers.

Gross mass

See : Mass.

Heat durability

The extent to which a material retains its useful properties at ambient air conditions,following its exposure to a specified temperature and environment for a specified timeand its return to ambient air conditions.

Heat resistance

The extent to which a material retains useful properties as measured during exposure ofthe material to a specified temperature and environment for a specified time.

High tenacity yarn

A yarn with a significantly higher breaking tenacity than others of the same genericcategory, generally used because of that main characteristic.Note : Currently the following lower limits are used for high tenacity yarns :


34

Table 3.1 : Limits for high tenacity filament yarns

Generic category offibre

Lower limit oftenacity (cN/tex)

Aramide 180

Polyamide/Nylon 53

Polyester 53

Viscose 28

Hot air shrinkage, after treatment

See : Shrinkage.

Hot air shrinkage, during treatment

See : Shrinkage.

Industrial fibre

Fibres intended for use in products other than non-protective clothing, household,furnishing and floor coverings selected principally but not exclusively for theirperformance and properties as opposed to their aesthetic or decorative characteristics.

Initial length

The length of a test specimen under specified pretension at the beginning of a test.Note : For a tensile test the initial length is measured between the two effective

clamping points.

Interlaced yarn (Synonym: Intermingled yarn)

A multifilament yarn in which cohesion is imparted to the filaments usually by passing theyarn through a turbulent air-, gas- or steam-jet without overfeed causing entwining of thefilaments and the formation of randomly distributed interlacing points.

Interlacing distance

The distance between adjacent interlacing points.

Interlacing frequency

The number of interlacing points per unit length.

Intermingled yarn

See : Interlaced Yarn.


35

Invoice mass

See : Mass.

Jaw faces

The elements of a clamp which grip the test specimen without damaging it and whichprevent slippage during the test.

Knit-deknit yarn

A textured filament yarn obtained by a process in which the filament yarn is knitted, heatset and subsequently unravelled.

Laboratory sample

A portion of the contents of the containers in the consignment sample to be taken to thelaboratory for testing.The laboratory samples must be taken in such a way that collectively they represent thewhole consignment.

Latent crimp

See : Crimp.

Lay

Term in common use in cordage and steel cord industry, similar to twist in the textileindustry.

Direction of lay:

The helical disposition of the component, of a filament, strand or cord. Direction of layis in the "S" or left hand lay ("Z" or right hand lay) when the components of a filament,strand or cord held vertically slope in the same direction as the middle part of theletter S (or Z).See : Twist.

Lang's lay

Cord in which the direction of lay in the stranding is the same as the direction of lay incabling the cord.

Length of lay

The axial distance required to make a 360 degree revolution of any element in strandor cord.

Ordinary or regular lay

Cord in which the direction of lay in the stranding is opposite to the direction of lay incabling the cord.


36

Linear density

The mass per unit length of an essentially linear structure, for example of a staple fibre,filament yarn, tow or cord.See Chapter 6 : SI units.

Lot

All the products of one defined type and homogeneous quality delivered to onecustomer against one dispatch note.Note : The term lot is sometimes used for the whole consignment and sometimes for a

part of a consignment. See : Consignment

Lubricant

A chemical composition such as a fatty or waxy substance applied to a yarn in order toreduce friction in subsequent textile operations, such as knitting.

Mass

See also Chapter 6 : SI units

Commercial mass

The mass obtained by adding to the oven-dry mass of the material the masscorresponding to the conventional allowance and any additions specified in theBISFA methods.

II nvoice mass

The mass indicated on the invoice and used as a commercial basis for charging. InBISFA the invoice rnass should not normally differ from the commercial mass bymore than the tolerance of commercial mass.

Gross mass

The total mass of a consignment, or of any part of a consignment, including the fibreand the tare.

Net mass

The difference between the gross mass and the corresponding tare, determined atthe same time.

Oven-dry mass

The mass obtained by drying the fibre, usually after removal of added products suchas finish or oil and of extractable matters.


37

Tare

The sum of the masses of all the pallets, wrappers and containers, tie bands, and ifappropriate all the yam supports such as bobbins, tubes, relating to a consignment orto any part of a consignment.

Tolerance of commercial mass

The maximum permissible deviation between the value of the commercial mass asdetermined according to BISFA rnethods and the value indicated on the documentsof sale of the consignment. The tolerance of commercial mass is normally expressedas a percentage of the invoice mass.

Matrix fibre

Multicomponent fibre in which discrete and discontinuous portions of one or morepolymers are embedded in a matrix of another polymer.

Matrix fibril fibre

See : Matrix fibre.

Mean length

See : Fibre length.

Modulus (see also Fig. 3.1)

The property of a material representative of its resistance to deformation. In tensiletesting the modulus is expressed as the ratio of tenacity to strain.

Chord modulus

In a tenacity-strain curve, the ratio of the change in tenacity to the change in strainbetween two specified points on the curve.

Fo

rce

(Ten

acit

y)

Elongation [%]

Chord Modulus


38

Secant modulus

The secant modulus is a special case of chord modulus : starting at zero.

Tangent modulus

In a tenacity-strain curve, the ratio of the change in tenacity to the change in strainderived from the tangent at any point on the curve.

Modulus, wet

The modulus determined when the material is completely wet.In the definition of the generic name "modal", the term "wet modulus" is defined as thetenacity required to produce an elongation of 5 % when the specimen is completelyimmersed in water.

Moisture content

The amount of water contained in a material, expressed as a percentage of its totalmass (including moisture and any extractables).

Fo

rce

(Ten

acit

y)

Elongation [%]

Tangent Modulus

Fo

rce

(Ten

acit

y)

Elongation [%]

Secant Modulus


39

Moisture regain

The amount of water contained in the material expressed as a percentage of its oven-dry mass.

Monofilament yarn (Monofil)

Filament yarn consisting of a single filament.

Multicomponent fibre

Fibre composed of two or more fibre forming polymer components, which arechemically or physically different or both. Components can have arrangements such asside-by-side core-sheath or matrix. Where there are only two components, the fibre issaid to be bicomponent.

Multifilament yarn (Multifil)

Filament yarn consisting of two or more filaments.

Multiple wound yarn (Synonym: Assembled yarn)

A yarn without twist composed of two or more singles, folded or cabled yarns.

Net mass

See : Mass

Nominal length

See : Fibre length

Nominal linear density

The linear density mentioned on the documents of sale (contracts, invoices, etc.).

Open cord

A steel cord in which the wires have a periodic loose association which permits "rubber"to penetrate the cross-section.

Oven dry mass

See : Mass.

Package

A package consists of yarn or cord with its winding support, if used.Note : Packages may be of various shapes and winding patterns, e.g. bobbins, pirns,

cones, cops, hanks, cakes, cheeses, tubes, beams.


40

Permanent deformation

The unrecovered strain of an exercised specimen, measured after a specific recoveryperiod and expressed as percentage of the initial length of the specimen.

Plied yarn

See : Folded yarn.

POY

Abbreviation for partially oriented yam, used for filament yarns with a significant degreeof residual drawability. Such yarns are designed to be submitted to a further orientationprocess.

Preconditioning

The process of bringing a textile material to approximate equilibrium with theatmosphere for preconditioning.

Pre-dip

A chemical composition applied to a cord or fabric to improve the reactivity of thesurface.

Pretension

The specified tension applied to a test specimen preparatory to making a test.

Pulp

Pulp is a generic term for the processed fibrous material manufactured for different end-uses such as fibres, paper, compounds.

Relative humidity

The ratio, expressed as a percentage, of the pressure of water vapour actually presentin the atmosphere to the saturation pressure at the same temperature and at the sametotal pressure.

Residual torsion

The number of revolutions made by a specific length of steel cord when one end is heldin a fixed position and the other allowed to turn freely.

RFP

See : Dust

Roving

An indefinitely long assembly of staple fibres, substantially parallel, with slight twist,capable of being drafted in the later or final stages of preparation for spinning.See : Sliver.


41

Sample

A representative portion of a lot of material or of a consignment for testing or for recordpurposes.

Shrinkage

The decrease in length of a test specimen caused by a specified treatment, expressedas a percentage of the length of the untreated test specimen. The lengths are measuredbefore and during or after treatment under specified tensions.

Boiling water shrinkage

The decrease in length of a test specimen caused by a treatment in boiling water forspecified time, expressed as a percentage of the length of the untreated testspecimen. The lengths are measured before and after treatment under a specifiedpretension.

Hot water shrinkage

The decrease in length of a test specimen caused by a treatment in hot water under aspecified temperature and time, expressed as a percentage of the length of theuntreated test specimen. The lengths are measured before and after treatment undera specified pretension. The water temperature to be applied is specified betweenbuyer and seller.

Hot air shrinkage, after treatment :

The decrease in length of a test specimen caused by a treatment in hot air underspecified temperature and time, expressed as a percentage of the length of theuntreated test specimen. The lengths are measured before and after treatment undera specified pretension.

Hot air shrinkage, during treatment :

The decrease in length of a test specimen caused by a treatment in hot air underspecified temperature and time, expressed as a percentage of the length of theuntreated test specimen. The lengths are measured before (under a specifiedpretension) and during treatment (under a specified measuring tension).

Single yarn

A yarn composed of staple fibres (spun yarn), a single filament (monofilament) orseveral filaments (multifilament yarn), with or without twist.

Size

A chemical composition in solution or dispersion applied before weaving normally towarp, but sometimes to weft, to facilitate the weaving operations.


42

Sliver

An indefinitely long assembly of staple fibres, substantially parallel, without twist,capable of being drafted in preparation for spinning.See : Top, Roving.

Specimen

See : Test specimen.

Spun yarn

A yarn made of staple fibres usually bonded together by twist.

Square cut staple fibres

See : Staple fibre.

Stabilised false twist yarn

A yarn, having a low crimp elongation and a low crimp contraction, obtained by falsetwisting, followed by heat-setting in a state where it is only partly relaxed from thestraightened condition.

Standard atmosphere

See : Atmospheres

Staple fibre

A textile fibre of limited but spinnable length. For man-made fibres the three principalcategories are:

Square cut staple fibres:

Staple fibres obtained by cutting into bundles of essentially constant length; they arespecified by a single nominal length.

Stretch-broken fibres:

Staple fibres obtained by stretch-breaking a tow in a tow-to top process to a range oflengths up to a defined upper limit.

Variable length (or bias cut) staple fibres:

Staple fibres obtained by cutting in such a way as to deliberately introduce severallengths. Such fibres are specified by two finite nominal lengths corresponding to thelimits of the cut length.

Steel cord

A formed structure composed of two or more steel filaments when used as an endproduct or combination of strands or filaments and strands.


43

Steel filament

A steel fibre used as an individual element in a strand or cord.See : Filament.

Stiffness

Resistance to bending, characterised by the bending moment required to produce abent configuration under specified conditions.

Straightened length

The length of a test specimen under a specified tension sufficient to remove crimp.

Straightness

The ability of a steel cord to lie flat between two straight parallel lines which are aprescribed distance apart.

Strain

The ratio of the extension of a test specimen to its initial length.See : Elongation.

Strand

A general expression for linear textile assemblies, particularly yarns which arecomponents of ropes and cordage.Note for steel : A group of filaments twisted together to form a unit product to be

processed further. A strand may be considered as a cord if it is the endproduct for tyre reinforcement or if it may be an element in a morecomplex structure.

Strength at break

See : Breaking strength.

Stress

The resistance to deformation developed within a material subjected to an externalforce, expressed as force per cross-sectional area.Note : Sometimes wrongly used in textile testing for tenacity, which is force per linear

density.

Stretch-broken fibres

See : Staple fibre.

Stufferbox crimped yarn

Textured filament yarn obtained by overfeeding yam and compressing it into a chamber,which may be heated.


44

Tabby

A plain weave fabric. In the context of tyre cord fabric it refers to sections of closelyspaced weft yarns in a special section of fabric woven to provide a sample.

Tabby sample

The section of a tyre cord fabric between two tabbies.

Tangent modulus

See : Modulus.

Tangled yarn

Term sometimes used as alternative for interlaced yarn.See : Interlaced yarn.

Tare

See : Mass

Tenacity

Force divided by linear density.

Tenacity at break

See : Breaking tenacity

Tenacity at specified elongation

The tenacity associated with a specified elongation on the tenacity-elongation curve.

Tensile stress

The force per unit cross-sectional area of the unstrained specimen.

Tension

A force tending to cause the extension of a body.Note : An abbreviation for tensioning force. In fibres and yarns the tension applied is

usually based on the linear density of the material.

Tensioning force

See : Tension

Test specimen (Synonym : specimen)

A portion of a laboratory sample or, in certain cases, the entire laboratory sample to beused for a testing procedure.


45

Textured filament yarn

A filament yarn characterised by actual or latent filament crimps, coils or loops, with orwithout twist liveliness, by which it has, or can develop by after-treatment, bulk and/orstretch properties.

Titre (deprecated term)

See : Linear density.

Tolerance

The maximum permissible positive or negative deviation between the value of a quantityas determined according to BISFA methods and the value quoted for the consignment.Normally, the tolerance is a percentage of the quoted value.

Tolerance of commercial mass

See : Mass

Top

Synonym for sliver.Also a form of package in which sliver can be delivered, e.g.: ball top or bump top.

Torsion textured yarn

A textured filament yarn obtained by heat setting of a twisted filament yarn andsubsequently untwisting it.See : False Twist Yarn.

Toughness at break

See : Breaking toughness.

Tow

A large number of filaments, assembled without substantial twist usually intended to becut or stretch-broken for use in staple fibre or top form.

Twist

The helical disposition of the components of a single, folded or cabled yarn or roving.Twist is in the S (or Z) direction when the spirals of the yarn or roving held vertically slopein the same direction as the middle part of the letter S (or Z).See : International Standard ISO 2 (1973)


46

S ZNote : If the S/Z notation cannot be used (for example in numerical fields of databanks)

S should be designated as (-) and Z as (+).In steel cord the twist is called "direction of lay".

Twist factor

The value obtained when the twist is multiplied by the square root of the linear density ofthe yarn.

Note 1 :

1000

LD t TF =

where : TF = Twist Factort = Twist in turns per metreLD = Linear density in tex

Note 2 : In order to be able to make effective comparison of different fibre genericcategories in certain applications, e.g. tyre cords, it is necessary to take intoaccount the density of the fibres.

where : TFC = Twist Factor correctedt = Twist in turns per meterLD = Linear density in texp = Density in kg/m

Twist level

The number of turns per unit length of a twisted yarn.

Twist liveliness

The tendency for a twisted yarn to untwist or for a torsion textured yarn to resume itstwisted shape.

p

LD t TFc =


47

Type of lay

See : Lay

Tyre cord fabric

A structure used in tyre manufacture, comprising a sheet of warp cords or yarns boundtogether by widely spaced weft yarns which are usually of cotton and have a distinctlylower linear density than the warp cords or yarns.

Variable length (or bias cut staple fibres)

See : Staple fibre

Weight

Deprecated term still commonly but improperly used for mass.See : Mass.

Wet modulus

See : Modulus, Wet.

Wire

See : Steel Filament.

Work to break

The total area under the force extension curve up to the breaking force.

Wrap

A filament wound helically around a steel cord.

Yarn

A textile product of substantial length and relatively small cross section, composed offibre(s) with or without twist.This general term covers all the specific types of yarns, e.g. single yarn, multiple woundyarn, filament yarn, spun yarn.

Yarn length

The length of yarn wound on a support measured under defined conditions.


48

4.1 Definitions

Accuracy of measurement

The closeness of agreement between a test value and the accepted referencevalue.

Uncertainty of measurement

Parameter, associated with the result of a measurement, that characterizes thedispersion of the values that could reasonably be attributed to the measurand.

Bias

The difference between the accepted reference and the measured values. In abroader sense the bias can also be the difference between:- averages of results of two test procedures ;- averages of results obtained by two operators, laboratories etc. using the

same test procedure.

Component of variance

Is a portion of a total variance caused by a specific source.

In this BISFA-Terminology booklet three components of variance are considered.They are expressed as standard deviations.

Single operator component (s0)

The variance solely caused by the operator(s).

Within laboratories component (st)

The variance caused by instrument(s), environment (test atmosphere) in thelaboratory except the variance due to operator(s).This component is zero (0) when there is only operator(s) variability.

Between laboratories component (sL)

The variance caused by different laboratories. This component is zero (0) whenthere is only one laboratory.

CHAPTER 4Statistical terms and definitions


49

Precision

The closeness of agreement between independent test results obtained understipulated conditions.

Repeatability

The maximum absolute difference to be expected (95% probability) between testresults(1) of two measurements carried out directly in succession under the samerepeatability conditions.

Repeatability conditions

The same laboratory, sample, operator, equipment, at short time interval (nocalibrations).

Reproducibility within laboratories

The maximum absolute difference to be expected (95% probability) between testresults(1) of two measurements carried out on identical laboratory samples withinlaboratories but at long time intervals (different days, different equipment, anddifferent operators).

Reproducibility between laboratories

The maximum absolute difference to be expected (95% probability) between testresults(1) of two measurements carried out on identical laboratory samples but indifferent laboratories (different time, different equipment, different operators).Note (1) : a test result is always the average of a standard number of n

determinations.

4.2 Basic statistics

Individual value

The result of any one observation (breaking force, linear density, etc.) in a seriesof tests is called the individual value. The individual value of the ith observation ina series of n observations is denoted by xi.BISFA tests frequently involve the examination of more than one test specimentaken from a laboratory sample or sample. The resultant individual values shouldfirst be used to determine the laboratory sample/sample arithmetic mean and it isthis mean which should then be used as the individual value in subsequentstatistical calculations.

Normal distribution

In this booklet it is assumed that individual values follow a normal distribution inwhich the standard deviation s is independent from the mean. This distributionhas a bell shape symmetrical around the mean. Characteristics of this distributionare :


50

data of % 99.7 contains s x

data of % 95.0 contains s .96x

data of % 68.3 contains s 1 x

3

1

Frequency

Frequency is the number of individual values in each class. The number ofindividual values in the jth class is denoted by nj, k represents the number ofclasses. lt is recalled that :

Frequency distribution

For a large number of individual values (n > 50) it is advantageous to arrangeindividual values into classes with the same interval; a tabulation or diagramshowing the numbers of such values falling into defined class intervals is called afrequency distribution or histogram. lt is conventional to include within an intervalany observation which falls precisely on its upper boundary.The central value of a class is defined as the value equidistant between the twoclass boundaries.The class containing the greatest number of individual values is called modalclass.

=

=k

1 jjn n

Pro

babi

lity

x-2sx-3s x+3sx+2sx-s x+sx

NormalDistribution


51

Arithmetic mean

The arithmetic mean of a series of n individual values x1 , x2 , x3, is the sum ofthese values divided by their number, n:

In a frequency table made of k classes, the arithmetic mean is:

Yj = central value of the jth class

nj = frequency of the jth class

Overall arithmetic mean

It is the arithmetic mean of a set of individual values ignoring any sub-groups (seeindividual value) only if the sub-groups contain the same number of individualvalues.

Range (R)

The difference between the largest and the smallest values in a set ofobservations

Average range (R )

The average of a set of k ranges

(min) x - (max) x R =

n

x

n x ... x x

x

n

1 ii

n21==+++=

=+++=

=

n

yn

n

yn ... yn yn y

k

1 jjj

kk2211

m

x

m

x...x...xxx

m

1 jj

mj21

==+++++

=


52

Variance and standard deviation

The variance (s2) of a set of n individual values is the sum of the squares of thedifferences between each individual value and the arithmetic mean divided by(n - 1) :

The standard deviation of a set of individual values is the square root of thevariance:

These formulae can also be used for mean values when the tests have beendone with more than one test specimen from each laboratory sample, but in suchcases :

n = the number of samples

x i = the arithmetic mean of the sample

x = the overall arithmetic mean of laboratory sample

In the case of a frequency distribution, calculations are made with the followingformulae:

k

R

k

R ... R ... R R R

k

e

ke21

==+++

= 1e

( )1 - n

x - x s

n

1 i

2i

2

==

( )1 - n

x - x s

n

1 i

2i

==

( ) ( )1 - n

y - yn

s , 1 - n

y - y n

s

k

1 jjj

k

1 jjj

== ==

22

2


53

Universe standard deviation

An estimation of a true standard deviation based on a long series of k groups ofmeasurements and each group of which consists of n observations.

where :

Each group contains the same number of observations n and has a mean notsignificantly different from the others. d2 and c2 are factors used in connectionwith sampling by variables and they depend on n. (see Table 4.1).

Table 4.1 : Factors for estimate se

n d2 c2

2

3

4

5

6

7

8

9

10

1.1288

1.693

2.059

2.326

2.534

2.704

2.847

2.970

3.078

0.5642

0.7236

0.7979

0.8407

0.8686

0.8882

0.9027

0.9139

0.9227

Coefficient of variation

The ratio of the standard deviation to the arithmetic mean, expressed as apercentage :

2

e

2

e c

s or

d

R =s=s

k

s s and

k

R R

k

1 ii

k

1 i

== == i

( ) 100 y

s (%) V or 100

x

s V ==%


54

Confidence limits

In a consignment for which the individual measured values have practically anormal distribution, it is possible to define, symmetrically around the overallarithmetic mean x , an interval which contains in a given percentage of casesBISFA requires 95 %) the true arithmetic mean of the consignment under test.(This percentage is called confidence level)1

This interval from

is called the confidence interval.

are known as the confidence limits.

The half-length, c, of the confidence interval is thus for a given confidence level,the maximum value of the error made in estimating the true arithmetic mean2 ofthe consignment from the overall arithmetic mean. The half-length of theconfidence interval is given by the expression :

in which t is a coefficient, given in the following table as a function of n for therequired confidence level of 95 %, s is the standard deviation and n is the numberof individual values.

BISFA normally prefers to express the half-length c as a percentage C of theoverall arithmetic mean :

where V is the coefficient of variation.

1 Sometimes confidence level is expressed as a figure between 0 and 1, but (see ISO 2602) the expression as a percentage

is generally used.

2 BISFA considers that systematic errors are negligible, as the accuracy requirements on instruments are stringent

( ) ( ) c x to c - x +

( ) ( ) c x and c - x +

n

s t c =

( ) ( )n

(%)V t C or 100

x

c C =%=%


55

Table 4.2 : Values t0,975 of Students t-distribution with degree of freedomequals n+1

Number oftests n

t-value Number oftests

n

t-value Number oftests

n

t-value

4 3.18 15 2.14 25 2.06

5 2.78 16 2.13 26 2.06

6 2.57 17 2.12 27 2.06

7 2.45 18 2.11 28 2.05

8 2.36 19 2.10 29 2.05

9 2.31 20 2.09 30 2.04

10 2.26 21 2.09 31 to40 2.03

11 2.23 22 2.08 41 to 60 2.01

12 2.20 23 2.07 61 to 120 1.99

13 2.18 24 2.07 121 to 230 1.97

14 2.16 > 230 1.96

Note : If a probability other than 95% is desired, those Students t can be found instatistical books.

Measurements made with single test specimens do not always give values thatare normally distributed. Therefore it is necessary to do independent tests on aseries of test specimens, all taken from the consignment. For each laboratorysample a number of test specimens is tested and the arithmetic mean of theindividual values for that laboratory sample is calculated. The standard deviationof the arithmetic means of each laboratory sample with respect to the overallarithmetic mean is calculated. The confidence limits of the overall arithmeticmean can then be calculated from this standard deviation, using for n the numberof laboratory samples that have been tested.

Number of tests

For some determinations it may be necessary to increase the number of tests inorder to obtain a required confidence interval. If n tests have been made giving astandard deviation s or a coefficient of variation V, the resulting confidenceinterval may be too large. In order to obtain a required length of confidenceinterval c* or C*, the number of tests must be increased by m additional tests :

n - C

V t m or n -

c

s t m

2

22

22 ==


56

where t is the value corresponding to n in the above Table 4.2. In such casescalculate the mean and its confidence interval from the result of all (m + n) tests,and verify that the new confidence interval is satisfactory.

4.3 Statistical Process Control Parameters (SPC)

Process capability (6 ss )The limits of variability in which a process operates under normal conditions. lfthis variability is within 6 s, then the process is under statistical control.

Accuracy index (CA)

Index (expressed in percentage) indicating how close the process centering is tothe specified target

USL is the upper specification limitLSL is the lower specification limit.

Capability index (Cp)

Index relating the process capability to the specification tolerance

Quality index

CpkIt is the capability index, on a single set of data adjusted for process centering.

Where : se is the estimated standard deviation of the set of data considered.

010 LSL) - (USL 0.5

x - target Specified CA =

e

p 6

LSL- USL C

s=

s

s=

3

LSL - x ,

3

x - USL min C

eepk

mean. arithmetic overall the is x where


57

lf both CA and Cp are known, then

Ppk

The performance index measured on different sets of data and adjusted forprocess centering

where: ss is the estimated standard deviation of the data considered.

=

100

C - 1 C C Appk

=

ss ss 3LSL - x

, 3

x - USL min Ppk


58

5.1 Textile yarnsA standard notation for yarn construction is set out in the international standardISO 1139, edition 1973. The notation reflects in a condensed form details of thecomponents of a yarn, including values of the linear densities, direction of twist,twist level, number of folds, etc of these components and/or characteristics suchas linear density resulting from this construction.

Two methods for the notation of yarns are available. The "single to fold" notationstarts from the linear density of the single yarn ; the "fold to single" notation startsfrom the linear density of the resultant yarn. The symbols used in both systemsare identical ; the differences are in the order of presentation, the use of themultiplication sign (x) in the single to fold notation, and of the solidus (/) in the foldto single notation. Distinction between the two methods does not apply to singlespun yarn, monofilament and multifilament yarns without twist, nor to multiplewound yarns.

The following symbols are used :

R : symbol for resultant linear density, to be put before its numerical value,

f : symbol for filaments, to be put before the number of filaments,

t0 : symbol for zero twist ; other twist values are represented by the number ofturns per metre of the twisted yarn, preceded by S or Z to indicate twistdirection.If the S/Z notation cannot be used, for example in numerical fields of databanks, "S" should be designated as (-) and "Z" as (+), (see internationalstandard ISO 2, edition 1973 and Definition "Twist" in chapter 3).

The notation is best illustrated by examples:The following are taken in part from ISO 1139, edition 1973

CHAPTER 5Designation of yarns in the tex system


59

Table 5.1 : Examples of notations of textile yarns in the tex system

Type of yarn Single to fold notation Fold to single notation

Single yarns

Spun yarn

Monofilament yarn without twist

Monofilament yarn with twist

Multifilament yarn without twist

Multifilament yarn with twist

40 tex Z660

17 dtex f1

17 dtex f1 S800R17.4 dtex

133 dtex f40

133 dtex f40S1000 ; R136 dtex

R17.4 dtex f1S800 ; 17 dtex

R136 dtex f40S1000 ; 133 dtex

Multiple wound yarns with

Similar components

Dissimilar components

40 tex S155 x 2

(25 tex S420 + 60 tex Z80)

Folded yarns with

Similar components


34 tex S600 x 2Z400 ; R69.3 tex

(25 tex S420 + 60 tex Z80)R89.2 tex

R69.3 tex Z4400/2S600 ; 34 tex

R89.2 tex S360/(S420 +Z80)25 tex + 60 tex

Cabled yarns with

Similar components


20 tex Z 700 x 2 S 400 x3 Z 200R 132 tex

(20 tex Z700 x 3 S400 + 34tex S600) Z200

R 132 tex Z 200/3 S 400/2Z 700;20 tex

R96 tex Z200/(S600 +S400/3 Z700) ; 34 tex

Covered yarns

Single covered

(56 dtex ; C39 dtex) TS800 (17 dtex f1) : R56 dtex

Symbol C : linear density of elastane core (stretched)

Symbol TS : direction of twist (here S)

Symbol R : resultant linear density of the covered yarn


60

Notes :- Prefixes and mutiples shall be written without space.- A space shall be used to separate the different characteristics of the yarn

construction.- x or / used to mark multiple yarn components shall be separated with spaces.- Units shall be written with a space in accordance with ISO 1000.

Addition of the resultant linear density in the "single to fold" notation, and of thesingle yarn linear density in the "fold to single" notation, is not obligatory; suchinformation is separated from the preceding notation by a semi-colon. If notneeded, the direction of twist and the twist level may be omitted; however, thedescription of twistless yarns may include the symbol for zero twist.

Values of linear density and of twist level used in commercial transactions areusually nominal values and are subject to agreed tolerances. Values of thesetolerances which apply to the products of BISFA members can be found in theappropriate BISFA booklets.

5.2 Steel tyre cordThe nomenclature system describes the construction of steel tyre cord.

The description of the construction follows the sequence of manufacture of thecord i.e., starting with the innermost strand or wire and moving outwards.

5.2.1 Format

The full description of the cord is given by the following formula:

(N x F) x D + (N x F) x D + (N x F) x D + F x D

Where:N = number of strandsF = number of filamentsD = nominal diameter of filaments expressed in millimetres

5.2.1.1 Each part shall be separated by a plus (+) sign.

5.2.1.2 Brackets may be used to differentiate a part that consists of morethan one component, i.e.

(1 x 4) x 0.20 + (6 x 4) x 0.20 + 1 x 0.15


61

5.2.1.3 When N or F = 1 they should not be included in order to obtain thesimplest formula, i.e.

4 x 0.20 + (6 x 4) x 0.20 + 0.15

5.2.1.4 If the diameter is the same for two or more parts in sequence, itneeds only be stated at the end of the sequence. The diameter ofthe spiral wrap shall always be stated separately, i.e.

4 + (6 x 4) x 0.20 + 0.15

5.2.1.5 When the innermost strand or wire is identical to the adjacentstrands or wires the formula may be simplified by stating only thesum of the identical components and brackets need not be used,i.e.

7 x 4 x 0.20 + 0.15

5.2.2 Cord lay length and lay direction

5.2.2.1 The sequence or order in the designation of the lay length and ofthe lay direction follows the sequence of manufacturing i.e.,starting with the innermost strand and moving outwards.

7 x 4 x 0.20 + 0.15

lay length 10/20/3.5lay direction S/Z/S

10/S is the lay length and direction of strands20/Z is the lay length and direction of the cord3.5/S is the lay length and direction of the spiral wrap

5.2.2.2 Direction of lay

The helical disposition of the components of a strand or cord aredesignated according to the general rules given below

- strand used as an end product : S

- ordinary or regular lay cord : strand Scord Z

- Lang's lay cord : strand and cord S

- spiral wrap : opposite to the direction of thecord lay


62

5.2.2.3 Length of lay

The nominal length of lay for steel cord constructions shall bebased on the ISO R 388 - R 20 Series.

5.3. Open cord constructions

Open cord constructions are designated by adding OC behind the corddescription.

As an illustration, some examples of designation of steel cord construction aregiven hereunder.

Table 5.2 : examples of designation of steel cord construction

Type of construction Lay length (mm) Lay direction

4 x 0.25 OC 14 S

2 + 7 x 0.22 + 0.15 6.3/12.5/5 SSZ

3 x 0.20 + 6 x 0.35 10/18 SZ

3 + 9 + 15 x 0.175 + 0.15 5/10/116/3.5 SSZS

3 + 9 + 15 x 0.22 + 0.15 6.3/12.5/18/3.5 SSZS


63

Introduction

The International System of units (SI) was adopted as the system of measuring units bythe 11th General Conference of Weights and Measures in 1960. The InternationalStandard ISO 1000 gives full details of the recommended units and the ways in whichthey should be used.

This chapter does not cover all aspects of the system, it is limited to those which are ofparticular interest to the fibres and textiles industry.

6.1 Base units of the International System (SI)

The International System is founded on the following seven base units

Table 6.1

Quantity Abbreviationor symbol

Base unit Abbreviationor symbol

Length L metre m

Mass m kilogram kg

Time t second s

Electric current I ampere A

Thermodynamic temperature T kelvin K

Amount of substance n mole mol

Luminous intensity I candela cd

CHAPTER 6Application of SI units to man-made fibres


64

6.2 Derived units

The units for the measurement of other physical quantities are exclusively derivedfrom these base units. Distinction is made between :

a) Derived units which are described in terms of base units

These units are expressed algebraically as a function of base units. Theirsymbols are obtained using signs of multiplication and division, e.g. unit ofspeed, metre per second (symbol: m/s).

b) Derived units having names and special symbols which are subdividedinto two groups

Units of general application

These units are designated not by expression involving the base units, but by thenames and special symbols as set out in Table 6.2.

Table 6.2

Unit Expression asfunctionQuantity Symbol

Name Symbol SI base unit Derived

SI unit

Force F newton N kg . m . s-2

Pressure, stress p pascal Pa kg . m-1. s-2 . N . m-2

Energy, work,quantity of heat

E joule J kg . m2 . s-2 N . m

Power P watt W kg . m2 . s-3 J . s-1

Frequency f hertz Hz s-1

Units of specified application

These consist mainly of multiples or sub-multiples of derived SI units and arerestricted to special uses ; in particular the unit tex with its multiples andsubmultiples specifically for the textile industry. See Table 6.3.


65

Table 6.3

Quantity Name Symbol DerivedSI unit

Linear density

Linear density offibres and yarns

tex tex

kg/m

1 tex = 1 mg/m1 tex = 1 g/km

6.3 Multiples and sub-multiples

The names and symbols of the most commonly used decimal multiples andsubmultiples of the units are formed by the addition of the following prefixes(Table 6.4)

Table 6.4

Multiplication factorof the unit

Prefix Symbol

109 giga G

106 mega M

103 kilo k

102 hecto h

10 (or 101) deca da

10-1 deci d

10-2 centi c

10-3 milli m

10-6 micro

10-9 nano n

The prefix shall be bound to the name and the symbol of the prefix shall likewisebe bound to the symbol of the unit. In certain cases non-decimal multiples andsub-multiples may be used. For example a second of time has as a multiple aminute and a radian has as sub-multiples a degree in minutes and seconds.


66

6.4 Principal SI units in use for textiles

Mass

The SI System of units replaces the notion of weight by that of mass to describe aquantity of matter.

Linear Density

The SI unit of linear density is the kilogram per metre (kg/m).In the man-made fibre industry linear density is expressed in dtex (symbol: dtex).A fibre which has a mass of n grams per 10000

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